Tuesday, July 3, 2012
Age related declines in performance
Performance loss in triathlon occurs in a curvilinear fashion with relation to age. This means that initially, peak performance slowly drops with age, but the process of performance loss from year to year gets faster and faster. According to a study on master’s triathletes by Dr. Tanaka in 2008, there are relatively modest decreases until 50–60 years of age, with progressively steeper reductions after that. No one is immune from this: males and females as well as elite and non-elite athletes show similar patterns of decline, and in all three sports!
Another important question was asked by Dr. Brisswater’s group in 2010: What are the sport specific and distance specific declines with age? Perhaps unsurprisingly, this study found that cycling showed the least amount of age related changes at the Ironman and ITU / Olympic distance, and that there was less steep decline in overall performance over the Olympic distance than Ironman. Again, the sharpest declines seem to occur after age 50. Swimming showed the highest rate of decline in performance compared to cycling and running.
Why do these drops in performance occur with age? There are the obvious circumstances such as injury, but there are also interesting physiological changes that come with advancing years.
VO2max, the maximum amount of oxygen the body can process during hard exercise, has been shown in some studies to be the best predictor of age related changes in performance in Masters athletes. As you might expect, VO2max declines with age. It occurs at a rate of approximately 1% per year after the mid-30’s. Interestingly, this drop in VO2max is even higher in well-trained individuals compared to sedentary individuals.
I spoke to Dr. Phil Skiba about this. Dr. Skiba coached me during my World-Championship season, and is board-certified in sports medicine. “We do not completely understand the mechanism by which VO2max declines with age,” He told me, “However, it is important for athletes to know that it is possible to slow the decline by as much as ten-fold through hard, consistent training.” So, that means, do not neglect workouts that have short, hard intervals of 30 seconds up to 3 minutes for about 12-15 minutes of total work.
Since there are decreases in VO2max over time, we might question what happens to the lactate threshold (LT). LT denotes the point at which the muscles begin to become progressively more inefficient in terms of oxygen use, and begin to use greater amounts of carbohydrates for fuel. “LT is a very good predictor of exercise endurance and exercise performance, in some ways more important than VO2max per se.” said Dr. Skiba, “Importantly, it does not seem to decline in the same way with age, especially in athletes who remain fit and well-trained.” A healthy dose of LT intervals incorporated into your training program is a highly efficient way to delay drops in LT. These types of intervals are much longer in length than VO2 max intervals and can last from 10-20 minutes for about 40-60 minutes of total work depending upon one's level of fitness and the time of year.
A related subject is exercise economy, which is a measure of the amount of oxygen the body uses to do a particular task. For instance, if two athletes weigh the same, and are running at the same speed below LT, whichever athlete is using less oxygen is the one who is more economical. This does not seem to change very much with age, which is very good news indeed!
Now, of course, these are generalizations with respect to physiology, as not everyone experiences the same rates of decline for the same reasons. And, many Masters athletes report best times late in their careers, which would seem to suggest that most athletes are working so far below their true potential that they can manage to improve their performance in the face of a declining physiology. Dr. Skiba often uses the analogy of a ladder with his master’s athletes. “Imagine that your fitness is a ladder. The top of the ladder is VO2max. With age, you lose rungs from the top of the ladder. If you keep training, you can still climb higher and higher. Most people never get anywhere near the top, so they keep setting PR’s. They never realize they have lost the rungs above, because the ladder was so tall to begin with.”
As a master's runner, I have set PR's in the half marathon and marathon by incorporating a mixture of intervals from 30 seconds up to 20 minutes. While my VO2 max speed is slower than it was 10 years ago, I still make sure to work that high end to minimize the losses. And despite this slow down at the top end, I am clearly faster over the long distances. I just have to hope that none of my races come down to a finish chute sprint. But, then again, I never really had good top end speed. At the 2000 triathlon Olympic trials, my coach warned me, "If you are running neck and neck with someone, start sprinting with a mile to go."
Are you maximizing your potential? With a proper training program, you can certainly get closer to it!